Vehicle fuel tank

ABSTRACT

A fuel tank is provided which is blow molded for the simultaneous and integral formation of a hollow body including a multi-level bottom wall with pipes depending from different levels of the wall and being integrally formed therewith. Wells are provided which encircle the upper end portion of these pipes. In addition, a charging pipe is provided at the top of the tank. A valve is connected to the pipes depending from the bottom wall for selectively using the same.

United States Patent 1 Arakawa [4 1 Mar. 27, 1973 1 VEHICLE FUEL TANK [76] Inventor: Tsuneaki Arakawa, 14-24, 2-chome,

Tokyo, Japan [22] Filed: Aug. 3, 1970 [21] Appl. N0.: 60,239

[30] Foreign Application Priority Data Aug. 14, 1969 Japan ..44/76693 [52] US. Cl. ..l37/266, 137/546, 137/595 [51] Int. Cl. ..Fl7c 3/00 [58] Field of Search ..137/266, 255, 202, 264, 546, 137/572, 595, 802, 590, 571

[56] References Cited UNITED STATES PATENTS 3,518,977 7/1970 Smith ..137/595 X 1,109,582 9/1914 Gorton .....137/572 X 1,643,539 9/1927 Bossi ..l37/59O X 1,157,643 10/1915 Kuhn ..137/546 1,238,073 8/1917 Hollar ...l37/255 FOREIGN PATENTS OR APPLICATIONS 453,677 9/l936 Great Britain I 37/266 Primary Examiner-Henry T. Klinksiek Assistant ExaminerRobert J. Miller Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A fuel tank is provided which is blow molded for the simultaneous and integral formation of a hollow body including a multi-level bottom wall with pipes depending from different levels of the wall and being integrally formed therewith. Wells are provided which encircle the upper end portion of these pipes. In addition, a charging pipe is provided at the top of the tank. A valve is connected to the pipes depending from the bottom wall for selectively using the same.

4 Claims, 3 Drawing Figures BACKGROUND 1 Field of Invention This invention relates to fuel tanks of the type provided with two or more discharge pipes which are selectively employed according to the level of fuel contained within the associated tanks.

2. Prior Art It is known to provide fuel tanks according to conventional techniques, wherein there are employed two discharge pipes, one of which terminates at the bottom wall of the associated tank and the other of which projects into the tank above the bottom wall of the same. The pipe which projects into the fuel tank is used for the discharge of fuel from the tank until the level of fuel therein falls below a certain level, whereafter the other of the pipes is employed for purposes of discharge. Such construction has the disadvantage that it is not suitable for manufacture by economical techniques such as blow molding, whereas in addition, the construction is not suitable for use when the surface of the fuel is inclined or in cases where the surface of the fuel is disturbed as might occur when the associated vehicle is travelling over rough terrain or the like.

It is also known to provide a fuel tank with one discharge pipe located at the bottom thereof with a second discharge pipe located in a side wall thereof. If both of these pipes terminate at the respective walls of the tank, the objection is avoided that the fuel tank may not be manufactured by a blow molding techniques or the like. However, this construction is susceptible of criticism in that it does not account for the aforenoted difficulties which are encountered when the fuel surface in inclined within the tank or is otherwise disturbed.

SUMMARY OF INVENTION It is an object of the invention to provide an improved fuel tank construction which avoids the above noted deficiency.

It is another object of the invention to provide an improved fuel tank which is capable of being manufactured by blow molding techniques or the like.

Yet another object of the invention is to provide an improved fuel tank whose operation is not disturbed by the inclining of the fuel surface within the tank or other types of disturbances to which the fuel may be subjected.

In accordance with the invention there is provided a fuel tank which comprises a hollow body including a bottom wall with at least two levels therein and two discharge pipes respectfully connected to the bottom wall at different of the levels and extending downwardly from the bottom wall. These pipes include upper ends terminating at least substantially at the bottom wall. The pipes are preferably integral with the body and form a monolithic structure therewith. The bottom wall moreover includes well portions encircling the aforesaid end portions.

A charge pipe may also be integrally be connected with the body at a position spaced from the bottom wall.

The invention also relates to a method whereby the aforesaid construction is simultaneously and integrally blow molded from a plastic or other such material having suitable strength.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a sectional side view of a fuel tank in accordance with one embodiment of this invention;

FIG. 2 is a sectional side view of a conventional tank; and

FIG. 3 is a sectional side view of another tank having a defect which the invention cures.

DETAILED DESCRIPTION OF INVENTION A type of fuel tank is known for use in a vehicle, such as a motorcycle or the like, and wherein a tank body is provided with a pair of main and secondary fuel discharge pipes, the main pipe being used most of the time and the secondary pipe being used when the remaining amount of fuel falls below a predetermined amount.

In a conventional fuel tank, as shown in FIG. 2, a tank body a is formed with a substantially rectangular cross-section and main and secondary discharge tubes b and c are fixed thereto with their inserted portions having different relative heights. This construction is however not suitable for blow molding manufacturing techniques.

To provide a construction suitable for blow molding, there can be considered a construction, as shown in FIG. 3, wherein a tank body a is provided at a proper height in one side wall thereof with a main discharge pipe 11 and in the bottom wall thereof with a secondary discharge pipe 0 in such a manner that pipes b and c project integrally therefrom. This construction, however, involves the drawback that if the liquid surface of the fuel is disturbed or inclined during the use of the main discharge pipe b, the inner end opening of the pipe b' is often exposed above the liquid surface.

The invention has as an object of the provision of a blow-molded product free from the above-mentioned defects. According to this invention, a hollow tank body 1 (FIG. 1) is provided with a pair of main and secondary fuel discharge pipes 2 and 3 which are simultaneously and integrally formed with the tank by blow molding from a plastic or metal. The main fuel discharge pipe 2 is provided at almost the center of the bottom wall of the tank body 1 and projects downwardly. The bottom wall of the tank body 1 is expanded downward at one side of the center to have a plurality of difierent levels and to form integrally a subsidiary fuel chamber 4. The secondary fuel discharge pipe 3 is provided at the bottom wall of the chamber 4 and also projects downwardly. The pipes are thus connected to different levels of the bottom wall and include upper end portions which terminate at the bottom wall. In the illustrated example, the bottom wall of the tank body 1 is depressed at the base end area of each pipe 2 and 3 to form wells or fuel retainers 5 and 6. This prevents the discharge of the fuel from being hampered by a disturbing or inclination of the liquid surface.

In almost the same manner as in the conventional construction, the two discharge pipes 2 and 3 are in communication with a carburetor 8 of an engine through a single common valve 7. The tank body 1 has, on its upper surface, a projecting fuel inlet opening 9 which is also formed simultaneously and integrally with the tank by blow molding. Element 10 is a cap mounted thereon.

According to this invention, the main and secondary discharge pipes 2 and 3 are provided on the bottom wall of the tank body to project downwardly so that it is easy to form them simultaneously and integrally by blow molding. Each discharge pipe 2 or 3 opens into the bottom of the tank body 1 whereby the defect which occurs when a pipe is opened at the side surface of the tank body (FIG. 3) is avoided. Additionally, the tank body 1 is expanded downwardly at a portion of the bottom surface thereof to form the subsidiary fuel chamber 4, the secondary discharge pipe 3 being arranged to project from the bottom surface of the chamber 4 so that the reserve fuel can be securely obtained by a change over operation.

What is claimed is:

1. A fuel tank for a vehicle comprising a hollow body including a bottom wall with two levels and main and secondary discharge pipes respectively connected to the bottom wall at the different levels and extending downwardly from the bottom wall, said main discharge pipe being connected at the higher of the two levels,

said pipes including upper ends terminating, at least substantially, at the bottom wall; said main discharge pipe being located substantially centrally in said hot- 1 tom wall, said hollow body being completely open in its interior and providing free and unrestricted flow of fuel between said levels so that when the fuel fills the tank to a height above the higher level the fuel will have a common surface at both levels, said body including side walls which are continuous and non-apertured, and a top wall, and an inlet pipe integral with the top wall.

2. A tank as claimed in claim 1 wherein said bottom wall includes flat cylindrical well portions encircling said ends of the pipes and integral therewith.

3. A tank as claimed in claim 2 wherein the bottom wall at said well portions are parallel to one another at said different levels.

4. A tank as claimed in claim 3 wherein said bottom wall at said well portions have apertures which open directly into the interior of the hollow body and lead directly to said ends of the pipes. 

1. A fuel tank for a vehicle comprising a hollow body including a bottom wall with two levels and main and secondary discharge pipes respectively connected to the bottom wall at the different levels and extending downwardly from the bottom wall, said main discharge pipe being connected at the higher of the two levels, said pipes including upper ends terminating, at least substantially, at the bottom wall; said main discharge pipe being located substantially centrally in said bottom wall, said hollow body being completely open in its interior and providing free and unrestricted flow of fuel between said levels so that when the fuel fills the tank to a height above the higher level the fuel will have a common surface at both levels, said body including side walls which are continuous and non-apertured, and a top wall, and an inlet pipe integral with the top wall.
 2. A tank as claimed in claim 1 wherein said bottom wall includes flat cylindrical well portions encircling said ends of the pipes and integral therewith.
 3. A tank as claimed in claim 2 wherein the bottom wall at said well portions are parallel to one another at said different levels.
 4. A tank as claimed in claim 3 wherein said bottom wall at said well portions have apertures which open directly into the interior of the hollow body and lead directly to said ends of the pipes. 